Main plot

Sans tries his best to escape from the cage, but he encounters Muffet. With his abilities locked, Sans had to fend off desperately. Alphys suddenly appears, teleports Sans to the "Sanctuary", and is knocked down by Gaster after repelling Muffet with a magic gun.

        Sans found Gaster based on Alphys's cell phone location and fought with him. But Gaster was almost defeated, and Sans took advantage of the victory .They ran to Gaster's laboratory, where Papyrus died. Gaster distracts Sans with Papyrus's 'shadow' and then activates the Destruction Attack program, which makes sans suddenly thrown into a state of near-death, where he is able to communicate with Gaster at the soul level.

        Sans noticed that Gaster had a faint voice within his soul that did not belong to him, and they began to communicate. Sans soon learns the source of the jealousy.

        Sans and Gaster then join forces to separate jealousy and imprison it in a cage, after which Sans falls asleep weakly. The soul in the cage broke through the shackles, turned into a mist, and flew out.

Feeder 2

A long time ago, in a fog, determination, wistfulness, and jealousy were born. The three check each other. But jealousy grew stronger, affecting determination. In order not to let the balance be broken, wistfulness and jealousy end together, and their fragments are scattered everywhere.

        Gaster was born and tasted solitude. He found complete determination and fragments of wistfulness and jealousy. He created Sans out of wistfulness, and sans friends on a similar principle—he didn't want Sans to feel lonely.

        The remaining determination kept its distance from jealousy, but one day, Gaster put it all along. Jealousy in turn affects determination, and the fragments of the two merge to produce a stronger jealousy, looking for parasitic living bodies...